1. Field of the Invention
The present invention concerns a pre-moistened wiper comprising a nonwoven web having a majority of papermaking fibers, the web being impregnated with a modified guar gum, and a water based lotion containing borate ions for pre-moistening the web.
2. Description of the Prior Art
Flushable non-woven webs and fibrous batts have been made having temporary wet strength. One approach to obtain temporary wet strength employs a polyvinyl alcohol gelled with borate ions which gel breaks down in the presence of a large volume of water but retains strength temporarily in the presence of limited quantities of liquid. See for example U.S. Pat. No. 4,309,469 filed Apr. 13, 1979 and granted Jan. 5, 1982.
The prior art methods of obtaining temporary wet strength for a web are deficient with respect to maintaining wet strength over prolonged periods of time, (e.g., months) while wet with a water based lotion and subjected to extreme environmental conditions that can be encountered during shipment of commercial products and still be dispersible after use. Frequently, a product made by prior art methods lost its wet strength during prolonged contact with the water based lotion or lost its ability to disperse when immersed in large quantities of water after being exposed to elevated temperatures, e.g., 140.degree. F.
The use of guar gum in flushable fibrous sheet material is known. See U. S. Pat. No. 3,554,788. However, U.S. Pat. No. 3,923,592, in Example 3, describes guar gum as providing insufficient dry strength for a flushable product which is to retain a high percentage of its dry strength when wetted.